An organic electroluminescent element (hereinafter also referred to as “organic EL element”) using an organic electroluminescent material (hereinafter also referred to as “organic EL material”) is known as one type of light emitting element. An organic EL element has a structure in which a first electrode (anode), an organic layer, and a second electrode (cathode) are stacked. A display device in which an organic EL element is arranged in a pixel is classified into a bottom-emission type and a top-emission type depending on the direction of light emitted from a pixel. In the top-emission type display device, an electrode arranged on an upper surface of the organic layer, for example, a second electrode (cathode), is fabricated from a transparent conductive film such as indium tin oxide.
In an organic EL device, in the case when the second electrode (cathode) arranged on the organic layer is used as a surface for emitting light, the second electrode (cathode) is not only merely high in translucency but is required so that damage does not reach an organic layer which is an underlying surface when forming a transparent conductive film. A transparent conductive film such as indium tin oxide is fabricated by a sputtering method. When an electrode of an organic EL element is fabricated by a sputtering method, effort is put in devising the film deposition conditions so that the organic layer is not damaged by ions generated by a plasma or high energy electrons (for example, refer to Japanese Laid Open Patent Publications No. 2007-095338 and No. 2012-012633).
A display device in which pixels are formed with an organic EL element is arranged with a sealing layer is provided in a region where pixels are arranged so that the organic EL element does not deteriorate due to moisture or the like. If a pinhole, crack or defect due to a defect in the film is present in the sealing layer, moisture can enter from the defective part and the organic layer will deteriorate. There are various causes for defects being formed in a sealing layer. For example, if dust adheres to an underlying surface during the manufacturing process, it causes defects to be generated in the sealing layer.